Dell S4820T, Configuration Manual

Page: 995 / 1178

Configuring Root Guard
Enable STP root guard on a per-port or per-port-channel basis.
Dell Networking OS Behavior : The following conditions apply to a port enabled with STP root guard:
• Root guard is supported on any STP-enabled port or port-channel interface except when used as a
stacking port.
• Root guard is supported on a port in any Spanning Tree mode:
– Spanning Tree Protocol (STP)
– Rapid Spanning Tree Protocol (RSTP)
– Multiple Spanning Tree Protocol (MSTP)
– Per-VLAN Spanning Tree Plus (PVST+)
• When enabled on a port, root guard applies to all VLANs configured on the port.
• You cannot enable root guard and loop guard at the same time on an STP port. For example, if you
configure root guard on a port on which loop guard is already configured, the following error
message displays:
• % Error: LoopGuard is configured. Cannot configure RootGuard
.
• When used in an MSTP network, if root guard blocks a boundary port in the CIST, the port is also
blocked in all other MST instances.
To enable the root guard on an STP-enabled port or port-channel interface in instance 0, use the
following command.
• Enable root guard on a port or port-channel interface.
INTERFACE mode or INTERFACE PORT-CHANNEL mode
spanning-tree {0 | mstp | rstp | pvst} rootguard
–
0
: enables root guard on an STP-enabled port assigned to instance 0.
–
mstp
: enables root guard on an MSTP-enabled port.
–
rstp
: enables root guard on an RSTP-enabled port.
–
pvst
: enables root guard on a PVST-enabled port.
To disable STP root guard on a port or port-channel interface, use the
no spanning-tree 0
rootguard
command in an interface configuration mode.
To verify the STP root guard configuration on a port or port-channel interface, use the
show spanning-
tree 0 guard [interface interface ]
command in a global configuration mode.
Enabling SNMP Traps for Root Elections and Topology
Changes
To enable SNMP traps individually or collectively, use the following commands.
• Enable SNMP traps for spanning tree state changes.
snmp-server enable traps stp
• Enable SNMP traps for RSTP, MSTP, and PVST+ collectively.
snmp-server enable traps xstp
Spanning Tree Protocol (STP)
995